1. Field of the Invention
The present invention relates to a semiconductor device and more particularly relates to a semiconductor device including a compensation capacitance for power-source voltage.
2. Description of Related Art
In a semiconductor device such as a DRAM (Dynamic Random Access Memory), a compensation capacitance for power-source voltage is sometimes provided to stabilize an internal power-source voltage (see Japanese Patent Application Laid-open No. 2010-182392). A gate capacitance of a MOS transistor is generally used as the compensation capacitance for the power-source voltage.
However, when the gate capacitance is used as the compensation capacitance for the power-source voltage, it is necessary to form a MOS transistor for the compensation capacitance for the power-source voltage on a semiconductor substrate, which causes a problem of increasing the chip size. In addition, if the compensation capacitance for the power-source voltage becomes insufficient at a later stage of designing, it necessitates a change of a device layout on the semiconductor substrate to add an additional MOS transistor for increasing the compensation capacitance for the power-source voltage, which in turn causes a problem of increasing the time for development.